Inductive position sensor assembly

Abstract

In accordance with one embodiment of the present disclosure, an inductive sensor assembly includes a shaft and a multilayered printed circuit board (PCB). The shaft includes a first end. The first end has a bottom surface. A target including a flat forming a straight edge is integrally formed into the first end of the shaft. The PCB includes a transmitter coil and a two part receiving coil. The two part receiving coil has a first receiving coil and a second receiving coil. The first receiving coil is on a different layer of the PCB than the second receiving coil in an axial direction. The target is rotated about a central axis of the two part receiving coil. The straight edge of the target and the bottom surface is detected by the two part receiving coil.

I claim: 
     
       1. An inductive sensor assembly comprising:
 a shaft having a first end; 
 a target integrally formed from the first end of the shaft, the target having a first planar surface forming a straight edge, a first undercut portion forming a second planar surface integrally formed into the first end of the shaft, the second planar surface spaced apart from the first planar surface; and 
 a sensor assembly having a transmitter coil and a receiving coil, 
 wherein when the target is moved about a shaft axis, the straight edge and the first planar surface of the target is detected by the sensor assembly. 
 
     
     
       2. The inductive sensor assembly of  claim 1 , wherein the receiving coil of the sensor assembly is a two part receiving coil, the two part receiving coil having a first receiving coil and a second receiving coil. 
     
     
       3. The inductive sensor assembly of  claim 2 , further comprises:
 a multilayered printed circuit board (PCB), 
 wherein the transmitter coil, the first receiving coil and the second receiving coil are on a different layer of the PCB in an axial direction. 
 
     
     
       4. The inductive sensor assembly of  claim 2 , wherein the first receiving coil is a first plurality of crescents, each crescent of the first plurality of crescents has a first end and a second end, the first end begins adjacent to a central axis of the of the two part receiving coil and extending radially outward from the central axis of the two part receiving coil. 
     
     
       5. The inductive sensor assembly of  claim 4 , wherein the second receiving coil is a second plurality of crescents, each crescent of the second plurality of crescents has a first end and a second end, the first end is adjacent to the central axis of the two part receiving coil and extending radially outward from the central axis of the two part receiving coil, the second plurality of crescents being offset in an opposite direction with respect to the first plurality of crescents. 
     
     
       6. The inductive sensor assembly of  claim 5 , further comprising:
 a signal processor, 
 wherein the target integrally formed from the first end of the shaft and the arrangement of the first receiving coil and the second receiving coil corrects a nonsinusoidal input signal to the signal processor. 
 
     
     
       7. The inductive sensor assembly of  claim 2 , wherein:
 the target having a second straight edge, a second undercut portion forming a third planar surface integrally formed into the first end of the shaft, the second and third planar surfaces spaced apart from each other and equally spaced apart from the first planar surface. 
 
     
     
       8. The inductive sensor assembly of  claim 7 , wherein:
 the first receiving coil is a first plurality of hooks, each hook of the first plurality of hooks has a shank portion and a point portion, the shank portion beginning at an outer periphery of a central axis and tangentially extending radially in a generally radius pattern from the outer periphery of the central axis of the two part receiving coil, the point portion extending radially inward from the transmitter coil towards the central axis of the two part receiving coil. 
 
     
     
       9. The inductive sensor assembly of  claim 8 , wherein:
 the second receiving coil is a second plurality of hooks, each hook of the second plurality of hooks has a shank portion and a point portion, the shank portion beginning at the outer periphery of the central axis and tangentially extending radially in a generally radius pattern from the outer periphery of the central axis of the two part receiving coil, the point portion extending radially inward from the transmitter coil towards the central axis of the two part receiving coil, the second plurality of hooks being offset in an opposite direction with respect to the first plurality of hooks. 
 
     
     
       10. The inductive sensor assembly of  claim 2 , wherein:
 the target having a second straight edge and a third straight edge, a second undercut portion forming a third planar surface integrally formed into the first end of the shaft and a third undercut portion forming a fourth planar surface integrally formed into the first end of the shaft, the second, third and fourth planar surfaces spaced apart from each other and equally spaced apart from the first planar surface. 
 
     
     
       11. The inductive sensor assembly of  claim 10 , wherein:
 the first receiving coil is a first plurality of hooks, each hook of the first plurality of hooks has a shank portion and a point portion, the shank portion beginning at an outer periphery of a central axis and tangentially extending radially in a generally radius pattern from the outer periphery of the central axis of the two part receiving coil, the point portion extending radially inward from the transmitter coil towards the central axis of the two part receiving coil. 
 
     
     
       12. The inductive sensor assembly of  claim 11 , wherein:
 the second receiving coil is a second plurality of hooks, each hook of the second plurality of hooks has a shank portion and a point portion, the shank portion beginning at the outer periphery of the central axis and tangentially extending radially in a generally radius pattern from the outer periphery of the central axis of the two part receiving coil, the point portion extending radially inward from the transmitter coil towards the central axis of the two part receiving coil, the second plurality of hooks being offset in an opposite direction with respect to the first plurality of hooks. 
 
     
     
       13. The inductive sensor assembly of  claim 2 , wherein:
 the target having a second straight edge, a third straight edge and a fourth straight edge, a second undercut portion forming a third planar surface integrally formed into the first end of the shaft, a third undercut portion forming a fourth planar surface integrally formed into the first end of the shaft, and a fourth undercut portion forming a fifth planar surface integrally formed into the first end of the shaft, the second, third, fourth and fifth planar surfaces spaced apart from each other and equally spaced apart from the first planar surface. 
 
     
     
       14. The inductive sensor assembly of  claim 13 , wherein:
 the first receiving coil is a first plurality of hooks, each hook of the first plurality of hooks has a shank portion and an inverted point portion, the shank portion beginning at an outer periphery of a central axis and tangentially extending radially in a generally radius pattern from the outer periphery of the central axis of the two part receiving coil, the inverted point portion extending radially outward from the transmitter coil away from the central axis of the two part receiving coil. 
 
     
     
       15. The inductive sensor assembly of  claim 14 , wherein:
 the second receiving coil is a second plurality of hooks, each hook of the second plurality of hooks has a shank portion and an inverted point portion, the shank portion beginning at the outer periphery of the central axis and tangentially extending radially in a generally radius pattern from the outer periphery of the central axis of the two part receiving coil, the inverted point portion extending radially outward from the transmitter coil away from the central axis of the two part receiving coil, the second plurality of hooks being offset in an opposite direction with respect to the first plurality of hooks. 
 
     
     
       16. An inductive sensor assembly comprising:
 a shaft having a first end; 
 a target integrally formed from the first end of the shaft, the target having a first planar surface forming a straight edge, an undercut portion forming a second planar surface integrally formed into the first end of the shaft, the second planar surface spaced apart from the first planar surface; and 
 a sensor assembly comprising a printed circuit board (PCB), a transmitter coil and a two part receiving coil, the two part receiving coil comprising:
 a first receiving coil and a second receiving coil, the first receiving coil and the second receiving coil are on a different layer of the PCB in an axial direction, 
 wherein when the target is moved about a shaft axis, the straight edge and the first planar surface of the target is detected by the sensor assembly. 
 
 
     
     
       17. The inductive sensor assembly of  claim 16  wherein:
 the transmitter coil is a two part transmitter coil comprising an upper coil and a lower coil; 
 the PCB comprises at least four layers in the axial direction, the upper coil positioned on a first layer of the PCB, the lower coil positioned on a second layer of the PCB, the first receiving coil positioned on a third layer of the PCB and the second receiving coil positioned on a fourth layer of the PCB in the axial direction. 
 
     
     
       18. The inductive sensor assembly of  claim 17 , wherein the first receiving coil is a first plurality of crescents, each crescent of the first plurality of crescents has a first end and a second end, the first end begins adjacent to a central axis of the of the two part receiving coil and extending radially outward from the central axis of the two part receiving coil. 
     
     
       19. The inductive sensor assembly of  claim 18 , wherein the second receiving coil is a second plurality of crescents, each crescent of the second plurality of crescents has a first end and a second end, the first end is adjacent to the central axis of the two part receiving coil and extending radially outward from the central axis of the two part receiving coil, the second plurality of crescents being offset in an opposite direction with respect to the first plurality of crescents. 
     
     
       20. A method of determining a position of a movable shaft, the method comprising:
 milling a first end of a shaft to form a target, the target having a first planar surface forming a straight edge and an undercut portion forming a second planar surface, the second planar surface spaced apart from the first planar surface a predetermined distance such that the first planar surface is a coupler; 
 moving the target about a shaft axis; 
 exciting a transmitter coil; 
 obtaining a plurality of receiver signals from a sensor assembly; 
 determining the target positon based on the straight edge and the first planar surface; and 
 transmitting a corrected sinusoidal input signal to a signal processor.